Blister packs, typically formed of thin-walled clear molded plastic material for holding individual tablets, caplets or capsules, backed by a forcibly-tearable foil backing sheet, are well-known and in wide commercial use. The user of such an at least partially transparent blister pack can readily see the contents, e.g., items of medication, in each of several defined and individually sealed cavities therein. By applying force from the front to the foil behind a chosen cavity the user can cause a tear in the foil to thereby extract the contents of just that cavity. The other cavities remain sealed and retain their contents for similar access as needed in the future. Numerous cold and allergy remedies, headache and pain pills, and the like, are routinely stored, vended and dispensed in such packaging structures.
In another related context, manufacturers of drugs and pharmaceutical products often form small blister packs and provide them to medical practitioners as "samples" of newly developed medications. It is not unusual for one who visits a doctor with a complaint to be provided with one or more such sample blister packs by a doctor who is persuaded that the medication contained therein will be beneficial to the patient.
In yet another related use, businesses such as hotels and airlines also often maintain supplies of small blister packs in which correspondingly small quantities of medications are made readily available without charge to their customers or passengers.
Under all of the above-cited circumstances of normal use, there is always the danger that through neglect or inattention by an adult the blister pack will fall into the hands of a young child, e.g., one less than about four years old. For present purposes such a "young child" is one who has not learned and therefore cannot be expected to appreciate the danger in playing with or ingesting attractive but potentially harmful tablets, caplets, capsules or the like. Manufacturers of such products therefore have a serious interest in developing blister pack packaging which provides the advantages of rendering the contents of individual cavities or storage compartments visible, retains them in well-sealed condition pending use, allows responsible persons to access the contents of individual compartments readily, and yet resists efforts by a young child to access the contents of the individual compartments by chewing on, tearing up, or otherwise rupturing such a blister pack of any size.
One obvious way to make such a package childproof is to make the foil relatively thick and strong enough to resist tearing by a young child's teeth. Unfortunately, this will also defeat the purpose of allowing a responsible older child or adult to tear the foil to readily access the package contents. One known solution is to provide an additional peelable layer, e.g., of a film made of a plastic material adhered to the outside surface of the foil in what is sometimes called "peel-push" backing. Perforations may be provided in the added layer to facilitate its removal and one or more corner or edge portions thereof may be left unadhered to the underlying foil in an unobvious manner. A responsible person, but not a young child, may then easily peel and tear off part or all of the added-on protective layer to reach and tear the foil. Peelable adhesive materials for such applications are well known.
Surprisingly, although many adults display embarrassingly short attention spans, young children may often spend many minutes chewing on, banging on, or otherwise roughly handling small objects. When such a small object is a blister pack containing medications which the child should not play with or ingest, a few minutes of persistent chewing or gnawing on the conventional single foil or "peel-push" combination of a protective layer and foil may prove sufficient to allow the child the undesired access to the contents of the blister pack. In other words, when the basic concept is to simply "overpower" a young child solely by the strength of the package backing, the child's natural persistence may ultimately defeat such conventional protection and could lead to serious if not tragic results. It is therefore considered preferable to employ approaches which seek to outmaneuver or distract the young child away from efforts to open the package.
As more and more relatively powerful drugs become available and are vended in blister packs, or distributed as samples, the danger from improper ingestion of such materials by young children constantly increases. There is, therefore, a felt need for a blister pack structure which allows ready access by responsible individuals yet manages to outmaneuver, frustrate and/or quickly cause lack of interest in a very young child who handles a blister pack containing materials potentially harmful. The present invention addresses this need.